Light-induced transformation from diamagnetic ligand to paramagnetic radical offers a unique approach to modulating the magnetization dynamics of magnetic compounds.In this study,we present a two-dimensional Yb(III)co...Light-induced transformation from diamagnetic ligand to paramagnetic radical offers a unique approach to modulating the magnetization dynamics of magnetic compounds.In this study,we present a two-dimensional Yb(III)coordination polymer 1 and its Y(III)-diluted analog 1@Y,along with their lightinduced radical forms,1a and 1a@Y.Due to the presence of light-induced radicals,the magnetic susceptibility properties(_(χM)T values)of 1a and 1a@Y featured remarkable 82.3%and 88.9%enhancements,respectively,at room temperature,compared with those of 1 and 1@Y,and were accompanied by an unexpected increase in the effective energy barrier for magnetization dynamics.The magnetization dynamics of 1 and 1a involved both Orbach and Raman processes,while 1@Y and 1a@Y exhibited two Raman processes,indicating that the Orbach process that occurred in 1 and 1a was mainly attributed to the magnetic coupling between Yb(III)ions.This work showcases the potential of light-induced radical transformation for tuning both the static and dynamic magnetic properties of lanthanide coordination polymers.展开更多
We focus on the ferromagnetic thin films and review progress in understanding the magnetization dynamic of coherent precession, its application in seeking better high frequency magnetic properties for magnetic materia...We focus on the ferromagnetic thin films and review progress in understanding the magnetization dynamic of coherent precession, its application in seeking better high frequency magnetic properties for magnetic materials at GHz frequency, as well as new approaches to these materials＇ characterization. High frequency magnetic properties of magnetic materials determined by the magnetization dynamics of coherent precession are described by the Landau-Lifshitz-Gitbert equation. However, the complexity of the equation results in a lack of analytically universal information between the high frequency magnetic properties and the magnetization dynamics of coherent precession. Consequently, searching for magnetic materials with higher permeability at higher working frequency is still done case by case.展开更多
As a monoatomic bridge,fluoride ion can transmit efficient magnetic interaction between lanthanide ions but its effect on tuning the magnetization dynamics has not been well understood.Herein,two monofluoride-bridged ...As a monoatomic bridge,fluoride ion can transmit efficient magnetic interaction between lanthanide ions but its effect on tuning the magnetization dynamics has not been well understood.Herein,two monofluoride-bridged dinuclear dysprosium complexes[Dy_(2)F(bbpen)_(2)(Et OH)_(2)]Br·Et OH(1)and[Dy_(2)F(bbppy)_(2)]Br·2Et OH(2)with Dy-F-Dy angles of~178°and their diamagnetic-ion diluted analogues 1'and 2'were synthesized.Magnetic studies reveal that 1 and 1'barely show any magnetization dynamics,but 2 and 2'exhibit strong magnetization dynamics.Systematical experimental analysis combined with ab initio calculations reveals that the different magnetization dynamics between 1 and 2 mainly originate from the effect of magnetic anisotropy by terminal ligand and bridging group of the chelating ligand,and the fluoride bridge can effectively suppress the quantum tunneling of the magnetization and turn on Orbach process in 2.展开更多
BACKGROUND Colorectal cancer stands among the most prevalent digestive system malignancies.The microsatellite instability(MSI)profile plays a crucial role in determining patient outcomes and therapy responsiveness.Tra...BACKGROUND Colorectal cancer stands among the most prevalent digestive system malignancies.The microsatellite instability(MSI)profile plays a crucial role in determining patient outcomes and therapy responsiveness.Traditional MSI evaluation methods require invasive tissue sampling,are lengthy,and can be compromised by intratumoral heterogeneity.AIM To establish a non-invasive technique utilizing dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI)radiomics and machine learning algorithms to determine MSI status in patients with intermediate-stage rectal cancer.METHODS This retrospective analysis examined 120 individuals diagnosed with stage II/III rectal cancer[30 MSI-high(MSI-H)and 90 microsatellite stability(MSS)/MSI-low(MSI-L)cases].We extracted comprehensive radiomics signatures from DCE-MRI scans,encompassing textural parameters that reflect tumor heterogeneity,shapebased metrics,and histogram-derived statistical values.Least absolute shrinkage and selection operator regression facilitated feature selection,while predictive frameworks were developed using various classification algorithms(logistic regression,support vector machine,and random forest).Performance assessment utilized separate training and validation cohorts.RESULTS Our investigation uncovered distinctive imaging characteristics between MSI-H and MSS/MSI-L neoplasms.MSIH tumors exhibited significantly elevated entropy values(7.84±0.92 vs 6.39±0.83,P=0.004),enhanced surface-tovolume proportions(0.72±0.14 vs 0.58±0.11,P=0.008),and heightened signal intensity variation(3642±782 vs 2815±645,P=0.007).The random forest model demonstrated superior classification capability with area under the curves(AUCs)of 0.891 and 0.896 across training and validation datasets,respectively.An integrated approach combining radiomics with clinical parameters further enhanced performance metrics(AUC 0.923 and 0.914),achieving 88.5%sensitivity alongside 87.2%specificity.CONCLUSION DCE-MRI radiomics features interpreted through machine learning frameworks offer an effective strategy for MSI status assessment in intermediate-stage rectal cancer.展开更多
BACKGROUND Rectal cancer requires accurate preoperative assessment of T stage and differentiation grade for treatment planning.Traditional imaging and serum markers have limitations in diagnostic accuracy.AIM To evalu...BACKGROUND Rectal cancer requires accurate preoperative assessment of T stage and differentiation grade for treatment planning.Traditional imaging and serum markers have limitations in diagnostic accuracy.AIM To evaluate the predictive value of dynamic contrast-enhanced-magnetic resonance imaging(DCE-MRI)parameters and serum biomarkers[carbohydrate antigen(CA)19-9,CA125]for determining T stage and differentiation grade in rectal cancer.METHODS We conducted a retrospective review of clinical data from 126 patients who were pathologically diagnosed with rectal cancer between January 2021 to June 2024.Each patient underwent DCE-MRI scans and serum tests for CA19-9 and CA125.Receiver operating characteristic curves were utilized to assess the diagnostic value of DCE-MRI parameters,including volume transfer constant(Ktrans),rate constant(Kep),and volume fraction of extravascular extracellular space(Ve),as well as serum biomarkers for staging and grading rectal cancer.The DeLong test algorithm was employed to evaluate differences in diagnostic performance among the various indicators.RESULTS There were statistically higher levels of Ktrans,Ve,CA19-9,and CA125 serum concentrations of patients with advanced T stages and on poorly differentiated tumors than that in patients with low stages and moderate to high differentiation(P<0.05).Combined use of Ktrans and Ve for T stage diagnosis showed an area under the curve(AUC)of 0.892[95%confidence interval(CI):0.832-0.952],which increased to 0.923(95%CI:0.865-0.981)when combined with serum biomarkers.For grades differentiation,the combined DCE-MRI parameters had an AUC of 0.883(95%CI:0.821-0.945),which rose to 0.912(95%CI:0.855-0.969)when combined with serum markers.According to the Delong test,the combined diagnostic method performed better than a single diagnostic method(P<0.05).CONCLUSION The combined application of DCE-MRI functional parameters and serum tumor markers can significantly improve the diagnostic accuracy of T staging and differentiation degree of rectal cancer,providing a new approach to improve the preoperative assessment system of rectal cancer.This combined diagnostic model has important clinical application value,but further validation is needed through large-scale multicenter studies.展开更多
The management of patients with colorectal cancer(CRC)mainly lies on the use of magnetic resonance imaging(MRI)technique as a diagnostic tool for both staging and restaging.AIM To explore the preoperative value of qua...The management of patients with colorectal cancer(CRC)mainly lies on the use of magnetic resonance imaging(MRI)technique as a diagnostic tool for both staging and restaging.AIM To explore the preoperative value of quantitative parameters of dynamic contrastenhanced MRI(DCE-MRI)in evaluating clinical stages of CRC.METHODS A total of 86 CRC patients undergoing DCE-MRI examinations were included and then classified into CRC group(n=46)and benign tumor group(n=40)according to surgical and pathological results.Quantitative parameters of DCE-MRI,including volume transfer constant(Ktrans),rate constant(Kep)and extravascular extracellular volume fraction(Ve),were analyzed between two groups and among CRC at different stages.Receiver operating characteristic(ROC)curves with of quantitative parameters of DCE-MRI for clinical diagnosis and preoperative staging of CRC were plotted.RESULTS The CRC group had 9 cases with tumor in the upper segment,21 cases in the middle segment,16 in the low segment,10 cases with well differentiation,27 cases with moderate differentiation,and 9 cases with poor differentiation.The Ktrans,Kep,and Ve in the CRC group were higher than those in the benign tumor group(P<0.05).The ROC curves indicated that the optimal cutoff values of Ktrans,Kep and Ve for diagnosing CRC were 0.905 minute-1,0.225 minute-1 and 0.585%,respectively.The Ktrans,Kep and Ve as a combined tool to diagnose CRC yielded 0.863 of area under the curve and 82.60%of sensitivity,and both values were higher than those yielded by Ktrans,Kep,or Ve alone(P<0.05).The Ktrans,Kep and Ve in CRC patients at T3-T4 stage or N1-N2 stage were higher than those at T1-T2 stage or N0 stage(P<0.05).Results of Spearman correlation analysis showed that the Ktrans,Kep and Ve were correlated with advanced T and N stages in CRC patients(P<0.05).The ROC results indicated that the Ktrans produced a higher specificity(81.48%)and sensitivity(94.70%)in evaluating preoperative T stage of CRC.The Kep generated a higher specificity(96.00%)and sensitivity(81.00%)in evaluating preoperative N stage of CRC.CONCLUSION The study suggests that the values of Ktrans,Kep and Ve of DCE-MRI exhibit good performance in diagnosing CRC and preoperative assessment of clinical stages.However,relatively small sample size should be considered for data interpretation.展开更多
BACKGROUND The role of cerebral microvascular dysfunction in early cognitive impairment and dementia has become increasingly recognized.Furthermore,pathological changes in both Alzheimer’s disease and vascular dement...BACKGROUND The role of cerebral microvascular dysfunction in early cognitive impairment and dementia has become increasingly recognized.Furthermore,pathological changes in both Alzheimer’s disease and vascular dementia are almost always associated with cerebral hemodynamic deficits.AIM To investigate the diagnostic performance of dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI)assessment of the blood-brain barrier(BBB)in combination with relevant plasma biomarkers for mild cognitive impairment(MCI).METHODS This study selected 50 patients with non-amnestic MCI(na-MCI group),52 patients with amnestic MCI(a-MCI group),and 55 healthy elderly controls(control group).The Chinese version of the Montreal cognitive assessment(MoCA),auditory verbal learning test(AVLT),Hamilton anxiety/depression scale(HAMA/HAMD),and activity of daily living(ADL)scales were used to analyze the characteristics of mental and behavioral symptoms of patients with MCI.The DCE-MRI technique was used to assess the contrast enhancement kinetics.The Patlak model was utilized to analyze the BBB permeability(volume transfer constants).Further,fasting blood was was used to quantify plasma homocysteine(Hcy),β-amyloid protein(Aβ)40,Aβ42,human phosphorylated tau-181 protein(p-tau181),intercellular adhesion molecule-1(ICAM-1),vascular cell adhesion molecule-1(VCAM-1),and plasminogen activator inhibitor-1(PAI-1)levels,as well as serum neurofilament light chain(NFL)and glial fibrillary acidic protein(GFAP)concentrations.RESULTS The na-MCI and a-MCI groups demonstrated significantly lower MoCA and AVLT-Huashan version scores,and statistically higher HAMA,HAMD,and ADL scores compared to the control group.Moreover,the a-MCI group showed notably higher HAMA,HAMD,and ADL scores compared to the na-MCI group.Cranial MRI results revealed significant disparities in cerebral blood flow in the left and right frontal lobes,temporal lobes,hippocampi,cuneus,precuneus,parietal lobes,basal ganglia,and occipital lobes between the a-MCI and na-MCI groups.Compared to healthy controls,patients with MCI demonstrated a smaller amplitude of hippocampal contrast enhancement kinetics and a slower decay rate,indicating smaller vascular volume and increased BBB permeability.Further,Hcy,p-tau181,ICAM-1,VCAM-1,PAI-1,and NFL levels were substantially higher in the a-MCI group than in the na-MCI group,whereas the Aβ42 level was significantly lower.We did not observe any significant differences in Aβ40 and GFAP levels.CONCLUSION Patients with MCI may have experienced cerebrovascular system changes in the hippocampal region.Disorders associated with changes in cerebral blood supply may begin before pathophysiological changes are visible by imaging,which provides references for the assessment and treatment of patients with cognitive disorders.Further,DCE-MRI provides a noninvasive approach to diagnose subtle BBB leakage associated with cerebrovascular pathology.展开更多
We investigate the carrier, phonon, and spin dynamics in the ferromagnetic semiconductor(In,Fe)Sb using ultrafast optical pump-probe spectroscopy. We discover two anomalies near T^(*)(~40 K) and T^(†)(~200 K) in the p...We investigate the carrier, phonon, and spin dynamics in the ferromagnetic semiconductor(In,Fe)Sb using ultrafast optical pump-probe spectroscopy. We discover two anomalies near T^(*)(~40 K) and T^(†)(~200 K) in the photoexcited carrier dynamics, which can be attributed to the electron-spin and spin-lattice scattering processes influenced by the magnetic phase transition and modifications in magnetic anisotropy. The magnetization change can be revealed by the dynamics of coherent acoustic phonon. We also observe abrupt changes in the photoinduced spin dynamics near T^(*)and T^(†), which not only illustrate the spin-related scatterings closely related to the long-range magnetic order, but also reveal the D'yakonov–Perel and Elliott–Yafet mechanisms dominating at temperatures below and above T^(†), respectively. Our findings provide important insights into the nonequilibrium properties of the photoexcited(In,Fe)Sb.展开更多
AIM: To evaluate the ability of the time-signal intensity curve (TIC) of the pancreas obtained from dynamic contrast-enhanced magnetic resonance imaging (MRI) for differentiation of focal pancreatic masses, especially...AIM: To evaluate the ability of the time-signal intensity curve (TIC) of the pancreas obtained from dynamic contrast-enhanced magnetic resonance imaging (MRI) for differentiation of focal pancreatic masses, especially pancreatic carcinoma coexisting with chronic pancreatitis and tumor-forming pancreatitis. METHODS: Forty-eight consecutive patients who underwent surgery for a focal pancreatic mass, including pancreatic ductal carcinoma (n = 33), tumor-forming pancreatitis (n = 8), and islet cell tumor (n = 7), were reviewed. Five pancreatic carcinomas coexisted with longstanding chronic pancreatitis. The pancreatic TICs were obtained from the pancreatic mass and the pancreatic parenchyma both proximal and distal to the mass lesion in each patient, prior to surgery, and were classified into 4 types according to the time to a peak: 25 s and 1, 2, and 3 min after the bolus injection of contrast material, namely, type-Ⅰ, Ⅱ, Ⅲ, and Ⅳ, respectively, and were then compared to the corresponding histological pancreatic conditions. RESULTS: Pancreatic carcinomas demonstrated type-Ⅲ (n = 13) or Ⅳ (n = 20) TIC. Tumor-forming pancreatitis showed type-Ⅱ (n = 5) or Ⅲ (n = 3) TIC. All islet cell tumors revealed type-Ⅰ. The type-Ⅳ TIC was only recognized in pancreatic carcinoma, and the TIC of carcinoma always depicted the slowest rise to a peak among the 3 pancreatic TICs measured in each patient, even in patients with chronic pancreatitis.CONCLUSION: Pancreatic TIC from dynamic MRI provides reliable information for distinguishing pancreatic carcinoma from other pancreatic masses, and may enable us to avoid unnecessary pancreatic surgery and delays in making a correct diagnosis of pancreatic carcinoma, especially, in patients with longstanding chronic pancreatitis.展开更多
Preoperative detection of lymph nodes（LNs） metastasis is always highly challenging for radiologists nowadays. The utility of quantitative dynamic contrast-enhanced magnetic resonance imaging（QDCE-MRI） in identifyi...Preoperative detection of lymph nodes（LNs） metastasis is always highly challenging for radiologists nowadays. The utility of quantitative dynamic contrast-enhanced magnetic resonance imaging（QDCE-MRI） in identifying LNs metastasis is not well understood. In the present study, 59 patients with histologically proven rectal carcinoma underwent preoperative QDCE-MRI. The short axis diameter ratio, long axis diameter ratio, short-to-long axis diameter ratio and QDEC-MRI parameters（Ktrans, Kep, fPV and Ve） values were compared between the non-metastatic（n=44） and metastatic（n=35） LNs groups based on pathological examination. Compared with the non-metastatic group, the metastatic group exhibited significantly higher short axis diameter（7.558±0.668 mm vs. 5.427±0.285 mm）, Ktrans（0.483±0.198 min-1 vs. 0.218±0.116 min^-1） and Ve（0.399±0.118 vs. 0.203±0.096） values（all P〈0.05）. The short-to-long axis diameter ratio, long axis diameter ratio, Kep and fPV values did not show significant differences between the two groups. In conclusion, our results showed that for LNs larger than 5 mm in rectal cancer, there are distinctive differences in the Ktrans and Ve values between the metastatic and non-metastatic LNs, suggesting that QDCE-MRI may be potentially helpful in identifying LNs status.展开更多
In many areas of oncology, dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI) has proven to be a clinically useful, non-invasive functional imaging technique to quantify tumor vasculature and tumor perfusio...In many areas of oncology, dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI) has proven to be a clinically useful, non-invasive functional imaging technique to quantify tumor vasculature and tumor perfusion characteristics. Tumor angiogenesis is an essential process for tumor growth, proliferation, and metastasis. Malignant lesions demonstrate rapid extravasation of contrast from the intravascular space to the capillary bed due to leaky capillaries associated with tumor neovascularity. DCE-MRI has the potential to provide information regarding blood flow, areas of hypoperfusion, and variations in endothelial permeability and microvessel density to aid treatment selection, enable frequent monitoring during treatment and assess response to targeted therapy following treatment. This review will discuss the current status of DCE-MRI in cancer imaging, with a focus on its use in imaging prostate malignancies as well as weaknesses that limit its widespread clinical use. The latest techniques for quantification of DCE-MRI parameters will be reviewed and compared.展开更多
Objective： To evaluate the feasibility of dynamic contrast-enhanced magnetic resonance imaging（DCEMRI） for predicting tumor response to radiotherapy in patients with suspected primary central nervous system（CNS） ...Objective： To evaluate the feasibility of dynamic contrast-enhanced magnetic resonance imaging（DCEMRI） for predicting tumor response to radiotherapy in patients with suspected primary central nervous system（CNS） germ cell tumors（GCTs）.Methods： DCE-MRI parameters of 35 patients with suspected primary CNS GCTs were obtained prior to diagnostic radiation, using the Tofts and Kermode model. Radiosensitivity was determined in tumors diagnosed 2 weeks after radiation by observing changes in tumor size and markers as a response to MRI. Taking radiosensitivity as the gold standard, the cut-off value of DCE-MRI parameters was measured by receiver operating characteristic（ROC） curve. Diagnostic accuracy of DCE-MRI parameters for predicting radiosensitivity was evaluated by ROC curve.Results： A significant elevation in transfer constant（K^trans） and extravascular extracellular space（Ve）（P=0.000）, as well as a significant reduction in rate constant（Kep）（P=0.000） was observed in tumors. K^trans, relative K^trans, and relative Kep of the responsive group were significantly higher than non-responsive groups. No significant difference was found in Kep, Ve, and relative Ve between the two groups. Relative K^trans showed the best diagnostic value in predicting radiosensitivity with a sensitivity of 100%, specificity of 91.7%, positive predictive value（PPV） of 95.8%, and negative predictive value（NPV） of 100%.Conclusions： Relative K^trans appeared promising in predicting tumor response to radiation therapy（RT）. It is implied that DCE-MRI pre-treatment is a requisite step in diagnostic procedures and a novel and reliable approach to guide clinical choice of RT.展开更多
Objective： To prospectively compare the discriminative capacity of dynamic contrast enhanced-magnetic resonance imaging（DCE-MRI） with that of^18F-fluorodeoxyglucose（^18F-FDG） positron emission tomography/computed...Objective： To prospectively compare the discriminative capacity of dynamic contrast enhanced-magnetic resonance imaging（DCE-MRI） with that of^18F-fluorodeoxyglucose（^18F-FDG） positron emission tomography/computed tomography（PET/CT） in the differentiation of malignant and benign solitary pulmonary nodules（SPNs）.Methods： Forty-nine patients with SPNs were included in this prospective study. Thirty-two of the patients had malignant SPNs, while the other 17 had benign SPNs. All these patients underwent DCE-MRI and ^18F-FDG PET/CT examinations. The quantitative MRI pharmacokinetic parameters, including the trans-endothelial transfer constant（K^trans）, redistribution rate constant（Kep）, and fractional volume（Ve）, were calculated using the Extended-Tofts Linear two-compartment model. The ^18F-FDG PET/CT parameter, maximum standardized uptake value（SUV（max））, was also measured. Spearman＇s correlations were calculated between the MRI pharmacokinetic parameters and the SUV（max） of each SPN. These parameters were statistically compared between the malignant and benign nodules. Receiver operating characteristic（ROC） analyses were used to compare the diagnostic capability between the DCE-MRI and ^18F-FDG PET/CT indexes.Results： Positive correlations were found between K^trans and SUV（max）, and between K（ep） and SUV（max）（P〈0.05）.There were significant differences between the malignant and benign nodules in terms of the K^trans, K（ep） and SUV（max） values（P〈0.05）. The areas under the ROC curve（AUC） of K^trans） K（ep） and SUV（max） between the malignant and benign nodules were 0.909, 0.838 and 0.759, respectively. The sensitivity and specificity in differentiating malignant from benign SPNs were 90.6% and 82.4% for K^trans; 87.5% and 76.5% for K（ep）; and 75.0% and 70.6%for SUV（max）, respectively. The sensitivity and specificity of K^trans and K（ep） were higher than those of SUV（max）, but there was no significant difference between them（P〉0.05）.Conclusions： DCE-MRI can be used to differentiate between benign and malignant SPNs and has the advantage of being radiation free.展开更多
We investigate the ultrafast spin dynamics of an antiferromagnet in a ferromagnet/antiferromagnet heterostructure Fe/GdFeO_(3) via an all-optical method.After laser irradiation,the terahertz spin precession is hard to...We investigate the ultrafast spin dynamics of an antiferromagnet in a ferromagnet/antiferromagnet heterostructure Fe/GdFeO_(3) via an all-optical method.After laser irradiation,the terahertz spin precession is hard to be excited in a bare GdFeO_(3) without spin reorientation phase but efficiently in Fe/GdFeO_(3).Both quasi-ferromagnetic and impurity modes,as well as a phonon mode,are observed.We attribute it to the optical modification of interfacial exchange coupling between Fe and GdFeO3.Moreover,the excitation efficiency of dynamics can be modified significantly via the pump laser influence.Our results elucidate that the interfacial exchange coupling is a feasible stimulation to efficiently excite terahertz spin dynamics in antiferromagnets.It will expand the exploration of terahertz spin dynamics for antiferromagnet-based opto-spintronic devices.展开更多
The axial magnetic force, induced by the complicated flux linkage distribution from rotor magnet and stator slotted, is constructed by different relative heights and calculated by 3D finite element method (FEM) to ana...The axial magnetic force, induced by the complicated flux linkage distribution from rotor magnet and stator slotted, is constructed by different relative heights and calculated by 3D finite element method (FEM) to analyze the dynamic characteristics for a DVD spindle motor. The axial magnetic force is designed to provide an axial stiffness, and govern the natural frequency of the dynamic performance. According to the simulation results and experimental measurements, the dynamic behaviors are significantly improved with a variation of relative height of rotor magnet and stator slotted on a DVD spindle motor.展开更多
G-protein-coupled receptors(GPCRs)mediate a wide range of cellular responses to various ligands or stimuli,and are the most important drug targets associated with human diseases.While major advances in GPCR structural...G-protein-coupled receptors(GPCRs)mediate a wide range of cellular responses to various ligands or stimuli,and are the most important drug targets associated with human diseases.While major advances in GPCR structural biology have greatly deepened our understanding of its activation mechanism,the highly complex changes in the structural dynamics of GPCRs during activation remain underdetermined and their links to physiological functions largely unknown.Solution nuclear magnetic resonance(NMR)spectroscopy is an essential technique that allows the characterization of protein structural dynamics at atomic level,and has been applied in the studies of GPCR structural-function relationship in the past decade.Herein,we summarize a few specific studies in which solution NMR methods were employed and provided novel insights into questions difficult to be addressed by other methods.展开更多
Objective The aim of this study was to investigate the application of mammography combined with breast dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI) for the diagnosis of early breast cancer. Methods Ma...Objective The aim of this study was to investigate the application of mammography combined with breast dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI) for the diagnosis of early breast cancer. Methods Mammography and DCE-MRI were performed for 120 patients with breast cancer(malignant, 102; benign; 18). Results The sensitivity of mammography for early diagnosis of breast cancer was 66.67%, specificity was 77.78%, and accuracy was 68.33%. The sensitivity of MRI for early diagnosis of breast cancer was 94.12%, specificity was 88.89%, and accuracy was 93.33%. However, the sensitivity of mammography combined with DCE-MRI volume imaging with enhanced water signal(VIEWS) scanning for early diagnosis of breast cancer was 97.06%, specificity was 94.44%, and accuracy was 96.67%. Conclusion Mammography combined with DCE-MRI increased the sensitivity, specificity, and accuracy of diagnosing early breast cancer.展开更多
Objective:To explore the application of dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI)with Extended Tofts Linear(ETL)model and extended tofts(ET)model in pathological grading of cervical cancer.Method:R...Objective:To explore the application of dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI)with Extended Tofts Linear(ETL)model and extended tofts(ET)model in pathological grading of cervical cancer.Method:Retrospective analysis was performed on 31 cases of patients admitted to Shaoxing People's Hospital from January 2016 to October 2019 who were pathologically confirmed to have cervical cancer.They underwent preoperative multistage pelvic DCE-MRI examination.Extended Tofts Linear and Extended Tofts hemodynamic model of cervical cancer were calculated separately,and the quantitative perfusion parameters including transport capacity constant(K^(trans)),the rate constant(K_(ep)),blood vessels,extracellular clearance volume fraction(V_(e)),blood vessels,and clearance volume fraction(V_(p)).According to the postoperative pathologic stage can be divided into low,medium and high differentiate cervical cancer group,the difference contrast of three groups of cervical cancer perfusion parameter were analyzed.The parameters with statistical significance were screened out,and the ROC curves for the differentiation of cervical cancer with different degrees were drawn.Result:The diagnostic efficacy of the quantitative parameters obtained by the two models in the pathological grading of cervical cancer was compared.The Ktrans values of the Exte Nded Tofts Linear model highly differentiated(0.518±0.180)min^(-1),poorly differentiated(1.032±0.408)min^(-1)and the Extended Tofts model highly differentiated(0.525±0.283)min^(-1),poorly differentiated(1.487±0.991)min^(-1)were significantly different between the highly differentiated and poorly differentiated groups(P<0.05).There were no significant differences in Kep,Ve and Vp between high and low differentiated cervical cancer groups(all P>0.05).There were no significant differences in Ktrans,Kep,Ve and Vp between the two models(all P>0.05).The AUC of Ktrans in the Exte Nded Tofts Linear model was greater than that of Ktrans in the Extended Tofts model for the identification of highly and poorly differentiated cervical cancers.Joint diagnosis:Logistic regression analysis was used to calculate the joint diagnostic probability values of Ktrans of the Extended Tofts Linear and Extended Tofts models,and the results showed that the AUC of the two models was greater than that of the single model.Conclusion:The Ktrans obtained by the Extended Tofts Linear model and the Extended Tofts DCE-MRI model had certain value for the pathological grading of high and low differentiated cervical cancer,and the overall efficacy of the former was better than the latter.Meanwhile,the differential value of the two models combined for the pathological grading of cervical cancer was better than that of the single model perfusion parameter,and the differential diagnosis sensitivity and specificity of the two models combined with Ktrans were the highest.展开更多
We investigate the dynamic behavior of the magnetic domain wall under perpendicular magnetic field pulses in fiat ferromagnetic nanowires using micromagnetic simulations. It is found that the perpendicular magnetic fi...We investigate the dynamic behavior of the magnetic domain wall under perpendicular magnetic field pulses in fiat ferromagnetic nanowires using micromagnetic simulations. It is found that the perpendicular magnetic field pulse can trigger the magnetic domain wall motion, where all the field torques axe kept on the plane of nanowire strip. The speed of magnetic domain walls faster than several hundreds of meters per second is predicted without the Walker breakdown for the perpendicular magnetic driving field stronger than 200mT. Interestingly, the dynamic behavior of the moving magnetic domain wall driven by perpendicular magnetic field pulses is explained by charging- and discharging-like behaviors of an electrical RC-circuit model, where the charging and the discharging of magnetic charges on the nanowire planes are considered. The concept of the RC-model-like dynamic characteristic of the magnetic domain wall might be promising for the applications in spintronic functional devices based on the magnetic domain wall motion.展开更多
BACKGROUND Ureteropelvic junction obstruction(UPJO)is a common congenital urinary tract disorder in children.It can be diagnosed as early as in utero due to the presence of hydronephrosis or later in life due to sympt...BACKGROUND Ureteropelvic junction obstruction(UPJO)is a common congenital urinary tract disorder in children.It can be diagnosed as early as in utero due to the presence of hydronephrosis or later in life due to symptomatic occurrence.AIM To evaluate the discrepancy between dynamic contrast-enhanced magnetic resonance urography(dMRU)and scintigraphy 99m-technetium mercaptoacetyltriglycine(MAG-3)for the functional evaluation of UPJO.METHODS Between 2016 and 2020,126 patients with UPJO underwent surgery at Robert DebréHospital.Of these,83 received a prenatal diagnosis,and 43 were diagnosed during childhood.Four of the 126 patients underwent surgery based on the clinical situation and postnatal ultrasound findings without undergoing functional imaging evaluation.Split renal function was evaluated preoperatively using scintigraphy MAG-3(n=28),dMRU(n=53),or both(n=40).In this study,we included patients who underwent surgery for UPJO and scintigraphy MAG-3+dMRU but excluded those who underwent only scintigraphy MAG-3 or dMRU.The patients were divided into groups A(<10%discrepancy)and B(>10%discrepancy).We examined the discrepancy in split renal function between the two modalities and investigated the possible risk factors.RESULTS The split renal function between the two kidneys was compared in 40 patients(28 boys and 12 girls)using scintigraphy MAG-3 and dMRU.Differential renal function,as determined using both modalities,showed a difference of<10%in 31 children and>10%in 9 children.Calculation of the relative renal function using dMRU revealed an excellent correlation coefficient with renal scintigraphy MAG-3 for both kidneys.CONCLUSION Our findings demonstrated that dMRU is equivalent to scintigraphy MAG-3 for evaluating split renal function in patients with UPJO.展开更多
基金supported by the National Natural Science Foundation of China(grant nos.22435002a,92156002,21971123,and 62401563)L.U.acknowledges the financial support of the research projects A-800079-00-00,A-8000017-00-00,and A-8001894-00-00 of the National University of Singapore(NUS)+1 种基金Ab initio calculations were done on the Advanced Supercomputer for Petascale Innovation,Research and Enterprise 2A(ASPIRE-2A)cluster of the Singapore National Supercomputing Centre(NSCCwww.nscc.sg)under project 11001278.The highperformance computational(HPC)resources of NUS(HPC-NUS)are gratefully acknowledged.The NUS Research Scholarship program supported W.H.
文摘Light-induced transformation from diamagnetic ligand to paramagnetic radical offers a unique approach to modulating the magnetization dynamics of magnetic compounds.In this study,we present a two-dimensional Yb(III)coordination polymer 1 and its Y(III)-diluted analog 1@Y,along with their lightinduced radical forms,1a and 1a@Y.Due to the presence of light-induced radicals,the magnetic susceptibility properties(_(χM)T values)of 1a and 1a@Y featured remarkable 82.3%and 88.9%enhancements,respectively,at room temperature,compared with those of 1 and 1@Y,and were accompanied by an unexpected increase in the effective energy barrier for magnetization dynamics.The magnetization dynamics of 1 and 1a involved both Orbach and Raman processes,while 1@Y and 1a@Y exhibited two Raman processes,indicating that the Orbach process that occurred in 1 and 1a was mainly attributed to the magnetic coupling between Yb(III)ions.This work showcases the potential of light-induced radical transformation for tuning both the static and dynamic magnetic properties of lanthanide coordination polymers.
基金supported by the National Basic Research Program of China(Grant No.2012CB933101)the National Natural Science Foundation of China(Grant Nos.11034004 and 51371093)+1 种基金the Program for Changjiang Scholars and Innovative Research Team in University,China(Grant No.IRT1251)the Specialized Research Fund for the Doctoral Program of Higher Education,China(Grant No.20130211130003)
文摘We focus on the ferromagnetic thin films and review progress in understanding the magnetization dynamic of coherent precession, its application in seeking better high frequency magnetic properties for magnetic materials at GHz frequency, as well as new approaches to these materials＇ characterization. High frequency magnetic properties of magnetic materials determined by the magnetization dynamics of coherent precession are described by the Landau-Lifshitz-Gitbert equation. However, the complexity of the equation results in a lack of analytically universal information between the high frequency magnetic properties and the magnetization dynamics of coherent precession. Consequently, searching for magnetic materials with higher permeability at higher working frequency is still done case by case.
基金supported by the National Key R&D Program of China(No.2018YFA0306002)the National Natural Science Foundation of China(Nos.21971123 and 21973046)the Natural Science Foundation of Tianjin(No.18JCJQJC47200)。
文摘As a monoatomic bridge,fluoride ion can transmit efficient magnetic interaction between lanthanide ions but its effect on tuning the magnetization dynamics has not been well understood.Herein,two monofluoride-bridged dinuclear dysprosium complexes[Dy_(2)F(bbpen)_(2)(Et OH)_(2)]Br·Et OH(1)and[Dy_(2)F(bbppy)_(2)]Br·2Et OH(2)with Dy-F-Dy angles of~178°and their diamagnetic-ion diluted analogues 1'and 2'were synthesized.Magnetic studies reveal that 1 and 1'barely show any magnetization dynamics,but 2 and 2'exhibit strong magnetization dynamics.Systematical experimental analysis combined with ab initio calculations reveals that the different magnetization dynamics between 1 and 2 mainly originate from the effect of magnetic anisotropy by terminal ligand and bridging group of the chelating ligand,and the fluoride bridge can effectively suppress the quantum tunneling of the magnetization and turn on Orbach process in 2.
基金Supported by the Natural Science Foundation of Fujian Province,China,No.2022J011460。
文摘BACKGROUND Colorectal cancer stands among the most prevalent digestive system malignancies.The microsatellite instability(MSI)profile plays a crucial role in determining patient outcomes and therapy responsiveness.Traditional MSI evaluation methods require invasive tissue sampling,are lengthy,and can be compromised by intratumoral heterogeneity.AIM To establish a non-invasive technique utilizing dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI)radiomics and machine learning algorithms to determine MSI status in patients with intermediate-stage rectal cancer.METHODS This retrospective analysis examined 120 individuals diagnosed with stage II/III rectal cancer[30 MSI-high(MSI-H)and 90 microsatellite stability(MSS)/MSI-low(MSI-L)cases].We extracted comprehensive radiomics signatures from DCE-MRI scans,encompassing textural parameters that reflect tumor heterogeneity,shapebased metrics,and histogram-derived statistical values.Least absolute shrinkage and selection operator regression facilitated feature selection,while predictive frameworks were developed using various classification algorithms(logistic regression,support vector machine,and random forest).Performance assessment utilized separate training and validation cohorts.RESULTS Our investigation uncovered distinctive imaging characteristics between MSI-H and MSS/MSI-L neoplasms.MSIH tumors exhibited significantly elevated entropy values(7.84±0.92 vs 6.39±0.83,P=0.004),enhanced surface-tovolume proportions(0.72±0.14 vs 0.58±0.11,P=0.008),and heightened signal intensity variation(3642±782 vs 2815±645,P=0.007).The random forest model demonstrated superior classification capability with area under the curves(AUCs)of 0.891 and 0.896 across training and validation datasets,respectively.An integrated approach combining radiomics with clinical parameters further enhanced performance metrics(AUC 0.923 and 0.914),achieving 88.5%sensitivity alongside 87.2%specificity.CONCLUSION DCE-MRI radiomics features interpreted through machine learning frameworks offer an effective strategy for MSI status assessment in intermediate-stage rectal cancer.
文摘BACKGROUND Rectal cancer requires accurate preoperative assessment of T stage and differentiation grade for treatment planning.Traditional imaging and serum markers have limitations in diagnostic accuracy.AIM To evaluate the predictive value of dynamic contrast-enhanced-magnetic resonance imaging(DCE-MRI)parameters and serum biomarkers[carbohydrate antigen(CA)19-9,CA125]for determining T stage and differentiation grade in rectal cancer.METHODS We conducted a retrospective review of clinical data from 126 patients who were pathologically diagnosed with rectal cancer between January 2021 to June 2024.Each patient underwent DCE-MRI scans and serum tests for CA19-9 and CA125.Receiver operating characteristic curves were utilized to assess the diagnostic value of DCE-MRI parameters,including volume transfer constant(Ktrans),rate constant(Kep),and volume fraction of extravascular extracellular space(Ve),as well as serum biomarkers for staging and grading rectal cancer.The DeLong test algorithm was employed to evaluate differences in diagnostic performance among the various indicators.RESULTS There were statistically higher levels of Ktrans,Ve,CA19-9,and CA125 serum concentrations of patients with advanced T stages and on poorly differentiated tumors than that in patients with low stages and moderate to high differentiation(P<0.05).Combined use of Ktrans and Ve for T stage diagnosis showed an area under the curve(AUC)of 0.892[95%confidence interval(CI):0.832-0.952],which increased to 0.923(95%CI:0.865-0.981)when combined with serum biomarkers.For grades differentiation,the combined DCE-MRI parameters had an AUC of 0.883(95%CI:0.821-0.945),which rose to 0.912(95%CI:0.855-0.969)when combined with serum markers.According to the Delong test,the combined diagnostic method performed better than a single diagnostic method(P<0.05).CONCLUSION The combined application of DCE-MRI functional parameters and serum tumor markers can significantly improve the diagnostic accuracy of T staging and differentiation degree of rectal cancer,providing a new approach to improve the preoperative assessment system of rectal cancer.This combined diagnostic model has important clinical application value,but further validation is needed through large-scale multicenter studies.
文摘The management of patients with colorectal cancer(CRC)mainly lies on the use of magnetic resonance imaging(MRI)technique as a diagnostic tool for both staging and restaging.AIM To explore the preoperative value of quantitative parameters of dynamic contrastenhanced MRI(DCE-MRI)in evaluating clinical stages of CRC.METHODS A total of 86 CRC patients undergoing DCE-MRI examinations were included and then classified into CRC group(n=46)and benign tumor group(n=40)according to surgical and pathological results.Quantitative parameters of DCE-MRI,including volume transfer constant(Ktrans),rate constant(Kep)and extravascular extracellular volume fraction(Ve),were analyzed between two groups and among CRC at different stages.Receiver operating characteristic(ROC)curves with of quantitative parameters of DCE-MRI for clinical diagnosis and preoperative staging of CRC were plotted.RESULTS The CRC group had 9 cases with tumor in the upper segment,21 cases in the middle segment,16 in the low segment,10 cases with well differentiation,27 cases with moderate differentiation,and 9 cases with poor differentiation.The Ktrans,Kep,and Ve in the CRC group were higher than those in the benign tumor group(P<0.05).The ROC curves indicated that the optimal cutoff values of Ktrans,Kep and Ve for diagnosing CRC were 0.905 minute-1,0.225 minute-1 and 0.585%,respectively.The Ktrans,Kep and Ve as a combined tool to diagnose CRC yielded 0.863 of area under the curve and 82.60%of sensitivity,and both values were higher than those yielded by Ktrans,Kep,or Ve alone(P<0.05).The Ktrans,Kep and Ve in CRC patients at T3-T4 stage or N1-N2 stage were higher than those at T1-T2 stage or N0 stage(P<0.05).Results of Spearman correlation analysis showed that the Ktrans,Kep and Ve were correlated with advanced T and N stages in CRC patients(P<0.05).The ROC results indicated that the Ktrans produced a higher specificity(81.48%)and sensitivity(94.70%)in evaluating preoperative T stage of CRC.The Kep generated a higher specificity(96.00%)and sensitivity(81.00%)in evaluating preoperative N stage of CRC.CONCLUSION The study suggests that the values of Ktrans,Kep and Ve of DCE-MRI exhibit good performance in diagnosing CRC and preoperative assessment of clinical stages.However,relatively small sample size should be considered for data interpretation.
文摘BACKGROUND The role of cerebral microvascular dysfunction in early cognitive impairment and dementia has become increasingly recognized.Furthermore,pathological changes in both Alzheimer’s disease and vascular dementia are almost always associated with cerebral hemodynamic deficits.AIM To investigate the diagnostic performance of dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI)assessment of the blood-brain barrier(BBB)in combination with relevant plasma biomarkers for mild cognitive impairment(MCI).METHODS This study selected 50 patients with non-amnestic MCI(na-MCI group),52 patients with amnestic MCI(a-MCI group),and 55 healthy elderly controls(control group).The Chinese version of the Montreal cognitive assessment(MoCA),auditory verbal learning test(AVLT),Hamilton anxiety/depression scale(HAMA/HAMD),and activity of daily living(ADL)scales were used to analyze the characteristics of mental and behavioral symptoms of patients with MCI.The DCE-MRI technique was used to assess the contrast enhancement kinetics.The Patlak model was utilized to analyze the BBB permeability(volume transfer constants).Further,fasting blood was was used to quantify plasma homocysteine(Hcy),β-amyloid protein(Aβ)40,Aβ42,human phosphorylated tau-181 protein(p-tau181),intercellular adhesion molecule-1(ICAM-1),vascular cell adhesion molecule-1(VCAM-1),and plasminogen activator inhibitor-1(PAI-1)levels,as well as serum neurofilament light chain(NFL)and glial fibrillary acidic protein(GFAP)concentrations.RESULTS The na-MCI and a-MCI groups demonstrated significantly lower MoCA and AVLT-Huashan version scores,and statistically higher HAMA,HAMD,and ADL scores compared to the control group.Moreover,the a-MCI group showed notably higher HAMA,HAMD,and ADL scores compared to the na-MCI group.Cranial MRI results revealed significant disparities in cerebral blood flow in the left and right frontal lobes,temporal lobes,hippocampi,cuneus,precuneus,parietal lobes,basal ganglia,and occipital lobes between the a-MCI and na-MCI groups.Compared to healthy controls,patients with MCI demonstrated a smaller amplitude of hippocampal contrast enhancement kinetics and a slower decay rate,indicating smaller vascular volume and increased BBB permeability.Further,Hcy,p-tau181,ICAM-1,VCAM-1,PAI-1,and NFL levels were substantially higher in the a-MCI group than in the na-MCI group,whereas the Aβ42 level was significantly lower.We did not observe any significant differences in Aβ40 and GFAP levels.CONCLUSION Patients with MCI may have experienced cerebrovascular system changes in the hippocampal region.Disorders associated with changes in cerebral blood supply may begin before pathophysiological changes are visible by imaging,which provides references for the assessment and treatment of patients with cognitive disorders.Further,DCE-MRI provides a noninvasive approach to diagnose subtle BBB leakage associated with cerebrovascular pathology.
基金supported by the National Key R&D Program of China (Grant No. 2024YFA1408502)the National Natural Science Foundation of China (Grant Nos. 92365102, 62027807, 12474107, and 12174383)+1 种基金the Chinese Academy of Sciences project for Yong Scientists in Basic Research (Grant No. YSBR-030)the Guangdong Basic and Applied Basic Research Foundation (Grant No. 2024A1515011600)。
文摘We investigate the carrier, phonon, and spin dynamics in the ferromagnetic semiconductor(In,Fe)Sb using ultrafast optical pump-probe spectroscopy. We discover two anomalies near T^(*)(~40 K) and T^(†)(~200 K) in the photoexcited carrier dynamics, which can be attributed to the electron-spin and spin-lattice scattering processes influenced by the magnetic phase transition and modifications in magnetic anisotropy. The magnetization change can be revealed by the dynamics of coherent acoustic phonon. We also observe abrupt changes in the photoinduced spin dynamics near T^(*)and T^(†), which not only illustrate the spin-related scatterings closely related to the long-range magnetic order, but also reveal the D'yakonov–Perel and Elliott–Yafet mechanisms dominating at temperatures below and above T^(†), respectively. Our findings provide important insights into the nonequilibrium properties of the photoexcited(In,Fe)Sb.
文摘AIM: To evaluate the ability of the time-signal intensity curve (TIC) of the pancreas obtained from dynamic contrast-enhanced magnetic resonance imaging (MRI) for differentiation of focal pancreatic masses, especially pancreatic carcinoma coexisting with chronic pancreatitis and tumor-forming pancreatitis. METHODS: Forty-eight consecutive patients who underwent surgery for a focal pancreatic mass, including pancreatic ductal carcinoma (n = 33), tumor-forming pancreatitis (n = 8), and islet cell tumor (n = 7), were reviewed. Five pancreatic carcinomas coexisted with longstanding chronic pancreatitis. The pancreatic TICs were obtained from the pancreatic mass and the pancreatic parenchyma both proximal and distal to the mass lesion in each patient, prior to surgery, and were classified into 4 types according to the time to a peak: 25 s and 1, 2, and 3 min after the bolus injection of contrast material, namely, type-Ⅰ, Ⅱ, Ⅲ, and Ⅳ, respectively, and were then compared to the corresponding histological pancreatic conditions. RESULTS: Pancreatic carcinomas demonstrated type-Ⅲ (n = 13) or Ⅳ (n = 20) TIC. Tumor-forming pancreatitis showed type-Ⅱ (n = 5) or Ⅲ (n = 3) TIC. All islet cell tumors revealed type-Ⅰ. The type-Ⅳ TIC was only recognized in pancreatic carcinoma, and the TIC of carcinoma always depicted the slowest rise to a peak among the 3 pancreatic TICs measured in each patient, even in patients with chronic pancreatitis.CONCLUSION: Pancreatic TIC from dynamic MRI provides reliable information for distinguishing pancreatic carcinoma from other pancreatic masses, and may enable us to avoid unnecessary pancreatic surgery and delays in making a correct diagnosis of pancreatic carcinoma, especially, in patients with longstanding chronic pancreatitis.
基金supported by the Provincial Key Clinical Specialty(Medical Imaging)Development Program from Health and Family Planning Commission of Hunan Province,China(No.2015/43)the Health and Family Planning Commission of Hunan Province,China(No.B2016060)the National Key Clinical Specialty(Oncology Department)Development Program from National Health and Family Planning Commission of China(No.2013/544)
文摘Preoperative detection of lymph nodes（LNs） metastasis is always highly challenging for radiologists nowadays. The utility of quantitative dynamic contrast-enhanced magnetic resonance imaging（QDCE-MRI） in identifying LNs metastasis is not well understood. In the present study, 59 patients with histologically proven rectal carcinoma underwent preoperative QDCE-MRI. The short axis diameter ratio, long axis diameter ratio, short-to-long axis diameter ratio and QDEC-MRI parameters（Ktrans, Kep, fPV and Ve） values were compared between the non-metastatic（n=44） and metastatic（n=35） LNs groups based on pathological examination. Compared with the non-metastatic group, the metastatic group exhibited significantly higher short axis diameter（7.558±0.668 mm vs. 5.427±0.285 mm）, Ktrans（0.483±0.198 min-1 vs. 0.218±0.116 min^-1） and Ve（0.399±0.118 vs. 0.203±0.096） values（all P〈0.05）. The short-to-long axis diameter ratio, long axis diameter ratio, Kep and fPV values did not show significant differences between the two groups. In conclusion, our results showed that for LNs larger than 5 mm in rectal cancer, there are distinctive differences in the Ktrans and Ve values between the metastatic and non-metastatic LNs, suggesting that QDCE-MRI may be potentially helpful in identifying LNs status.
文摘In many areas of oncology, dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI) has proven to be a clinically useful, non-invasive functional imaging technique to quantify tumor vasculature and tumor perfusion characteristics. Tumor angiogenesis is an essential process for tumor growth, proliferation, and metastasis. Malignant lesions demonstrate rapid extravasation of contrast from the intravascular space to the capillary bed due to leaky capillaries associated with tumor neovascularity. DCE-MRI has the potential to provide information regarding blood flow, areas of hypoperfusion, and variations in endothelial permeability and microvessel density to aid treatment selection, enable frequent monitoring during treatment and assess response to targeted therapy following treatment. This review will discuss the current status of DCE-MRI in cancer imaging, with a focus on its use in imaging prostate malignancies as well as weaknesses that limit its widespread clinical use. The latest techniques for quantification of DCE-MRI parameters will be reviewed and compared.
基金supported by Beijing Natural Science Foundation(No.7122029)
文摘Objective： To evaluate the feasibility of dynamic contrast-enhanced magnetic resonance imaging（DCEMRI） for predicting tumor response to radiotherapy in patients with suspected primary central nervous system（CNS） germ cell tumors（GCTs）.Methods： DCE-MRI parameters of 35 patients with suspected primary CNS GCTs were obtained prior to diagnostic radiation, using the Tofts and Kermode model. Radiosensitivity was determined in tumors diagnosed 2 weeks after radiation by observing changes in tumor size and markers as a response to MRI. Taking radiosensitivity as the gold standard, the cut-off value of DCE-MRI parameters was measured by receiver operating characteristic（ROC） curve. Diagnostic accuracy of DCE-MRI parameters for predicting radiosensitivity was evaluated by ROC curve.Results： A significant elevation in transfer constant（K^trans） and extravascular extracellular space（Ve）（P=0.000）, as well as a significant reduction in rate constant（Kep）（P=0.000） was observed in tumors. K^trans, relative K^trans, and relative Kep of the responsive group were significantly higher than non-responsive groups. No significant difference was found in Kep, Ve, and relative Ve between the two groups. Relative K^trans showed the best diagnostic value in predicting radiosensitivity with a sensitivity of 100%, specificity of 91.7%, positive predictive value（PPV） of 95.8%, and negative predictive value（NPV） of 100%.Conclusions： Relative K^trans appeared promising in predicting tumor response to radiation therapy（RT）. It is implied that DCE-MRI pre-treatment is a requisite step in diagnostic procedures and a novel and reliable approach to guide clinical choice of RT.
基金supported by the Jiangsu Province Natural Science Foundation (No. BK20161291)the Nantong Science Foundation of China (No. MS2201507)the Nantong Municipal Commission of Health and Family Planning Young Fund (No. WQ2014047)
文摘Objective： To prospectively compare the discriminative capacity of dynamic contrast enhanced-magnetic resonance imaging（DCE-MRI） with that of^18F-fluorodeoxyglucose（^18F-FDG） positron emission tomography/computed tomography（PET/CT） in the differentiation of malignant and benign solitary pulmonary nodules（SPNs）.Methods： Forty-nine patients with SPNs were included in this prospective study. Thirty-two of the patients had malignant SPNs, while the other 17 had benign SPNs. All these patients underwent DCE-MRI and ^18F-FDG PET/CT examinations. The quantitative MRI pharmacokinetic parameters, including the trans-endothelial transfer constant（K^trans）, redistribution rate constant（Kep）, and fractional volume（Ve）, were calculated using the Extended-Tofts Linear two-compartment model. The ^18F-FDG PET/CT parameter, maximum standardized uptake value（SUV（max））, was also measured. Spearman＇s correlations were calculated between the MRI pharmacokinetic parameters and the SUV（max） of each SPN. These parameters were statistically compared between the malignant and benign nodules. Receiver operating characteristic（ROC） analyses were used to compare the diagnostic capability between the DCE-MRI and ^18F-FDG PET/CT indexes.Results： Positive correlations were found between K^trans and SUV（max）, and between K（ep） and SUV（max）（P〈0.05）.There were significant differences between the malignant and benign nodules in terms of the K^trans, K（ep） and SUV（max） values（P〈0.05）. The areas under the ROC curve（AUC） of K^trans） K（ep） and SUV（max） between the malignant and benign nodules were 0.909, 0.838 and 0.759, respectively. The sensitivity and specificity in differentiating malignant from benign SPNs were 90.6% and 82.4% for K^trans; 87.5% and 76.5% for K（ep）; and 75.0% and 70.6%for SUV（max）, respectively. The sensitivity and specificity of K^trans and K（ep） were higher than those of SUV（max）, but there was no significant difference between them（P〉0.05）.Conclusions： DCE-MRI can be used to differentiate between benign and malignant SPNs and has the advantage of being radiation free.
基金Project supported by the National Key Research Program of China(Grant Nos.2018YFF01010303,2017YFB0702702,and 2016YFA0300701)the National Natural Sciences Foundation of China(Grant Nos.52031015,1187411,51427801,and 51871235)the Key Research Program of Frontier Sciences,Chinese Academy of Sciences(Grant Nos.QYZDJ-SSW-JSC023,KJZD-SW-M01,and ZDYZ2012-2).
文摘We investigate the ultrafast spin dynamics of an antiferromagnet in a ferromagnet/antiferromagnet heterostructure Fe/GdFeO_(3) via an all-optical method.After laser irradiation,the terahertz spin precession is hard to be excited in a bare GdFeO_(3) without spin reorientation phase but efficiently in Fe/GdFeO_(3).Both quasi-ferromagnetic and impurity modes,as well as a phonon mode,are observed.We attribute it to the optical modification of interfacial exchange coupling between Fe and GdFeO3.Moreover,the excitation efficiency of dynamics can be modified significantly via the pump laser influence.Our results elucidate that the interfacial exchange coupling is a feasible stimulation to efficiently excite terahertz spin dynamics in antiferromagnets.It will expand the exploration of terahertz spin dynamics for antiferromagnet-based opto-spintronic devices.
文摘The axial magnetic force, induced by the complicated flux linkage distribution from rotor magnet and stator slotted, is constructed by different relative heights and calculated by 3D finite element method (FEM) to analyze the dynamic characteristics for a DVD spindle motor. The axial magnetic force is designed to provide an axial stiffness, and govern the natural frequency of the dynamic performance. According to the simulation results and experimental measurements, the dynamic behaviors are significantly improved with a variation of relative height of rotor magnet and stator slotted on a DVD spindle motor.
文摘G-protein-coupled receptors(GPCRs)mediate a wide range of cellular responses to various ligands or stimuli,and are the most important drug targets associated with human diseases.While major advances in GPCR structural biology have greatly deepened our understanding of its activation mechanism,the highly complex changes in the structural dynamics of GPCRs during activation remain underdetermined and their links to physiological functions largely unknown.Solution nuclear magnetic resonance(NMR)spectroscopy is an essential technique that allows the characterization of protein structural dynamics at atomic level,and has been applied in the studies of GPCR structural-function relationship in the past decade.Herein,we summarize a few specific studies in which solution NMR methods were employed and provided novel insights into questions difficult to be addressed by other methods.
文摘Objective The aim of this study was to investigate the application of mammography combined with breast dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI) for the diagnosis of early breast cancer. Methods Mammography and DCE-MRI were performed for 120 patients with breast cancer(malignant, 102; benign; 18). Results The sensitivity of mammography for early diagnosis of breast cancer was 66.67%, specificity was 77.78%, and accuracy was 68.33%. The sensitivity of MRI for early diagnosis of breast cancer was 94.12%, specificity was 88.89%, and accuracy was 93.33%. However, the sensitivity of mammography combined with DCE-MRI volume imaging with enhanced water signal(VIEWS) scanning for early diagnosis of breast cancer was 97.06%, specificity was 94.44%, and accuracy was 96.67%. Conclusion Mammography combined with DCE-MRI increased the sensitivity, specificity, and accuracy of diagnosing early breast cancer.
文摘Objective:To explore the application of dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI)with Extended Tofts Linear(ETL)model and extended tofts(ET)model in pathological grading of cervical cancer.Method:Retrospective analysis was performed on 31 cases of patients admitted to Shaoxing People's Hospital from January 2016 to October 2019 who were pathologically confirmed to have cervical cancer.They underwent preoperative multistage pelvic DCE-MRI examination.Extended Tofts Linear and Extended Tofts hemodynamic model of cervical cancer were calculated separately,and the quantitative perfusion parameters including transport capacity constant(K^(trans)),the rate constant(K_(ep)),blood vessels,extracellular clearance volume fraction(V_(e)),blood vessels,and clearance volume fraction(V_(p)).According to the postoperative pathologic stage can be divided into low,medium and high differentiate cervical cancer group,the difference contrast of three groups of cervical cancer perfusion parameter were analyzed.The parameters with statistical significance were screened out,and the ROC curves for the differentiation of cervical cancer with different degrees were drawn.Result:The diagnostic efficacy of the quantitative parameters obtained by the two models in the pathological grading of cervical cancer was compared.The Ktrans values of the Exte Nded Tofts Linear model highly differentiated(0.518±0.180)min^(-1),poorly differentiated(1.032±0.408)min^(-1)and the Extended Tofts model highly differentiated(0.525±0.283)min^(-1),poorly differentiated(1.487±0.991)min^(-1)were significantly different between the highly differentiated and poorly differentiated groups(P<0.05).There were no significant differences in Kep,Ve and Vp between high and low differentiated cervical cancer groups(all P>0.05).There were no significant differences in Ktrans,Kep,Ve and Vp between the two models(all P>0.05).The AUC of Ktrans in the Exte Nded Tofts Linear model was greater than that of Ktrans in the Extended Tofts model for the identification of highly and poorly differentiated cervical cancers.Joint diagnosis:Logistic regression analysis was used to calculate the joint diagnostic probability values of Ktrans of the Extended Tofts Linear and Extended Tofts models,and the results showed that the AUC of the two models was greater than that of the single model.Conclusion:The Ktrans obtained by the Extended Tofts Linear model and the Extended Tofts DCE-MRI model had certain value for the pathological grading of high and low differentiated cervical cancer,and the overall efficacy of the former was better than the latter.Meanwhile,the differential value of the two models combined for the pathological grading of cervical cancer was better than that of the single model perfusion parameter,and the differential diagnosis sensitivity and specificity of the two models combined with Ktrans were the highest.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11474183,51371105 and 51177088the Korea Research Foundation(NRF) under Grant No 2010-0021735+1 种基金the Leading Foreign Research Institute Recruitment Program of Korea under Grant No 2010-00471the Science and Technology Department of Hubei Province under Grant No 2014BEC060
文摘We investigate the dynamic behavior of the magnetic domain wall under perpendicular magnetic field pulses in fiat ferromagnetic nanowires using micromagnetic simulations. It is found that the perpendicular magnetic field pulse can trigger the magnetic domain wall motion, where all the field torques axe kept on the plane of nanowire strip. The speed of magnetic domain walls faster than several hundreds of meters per second is predicted without the Walker breakdown for the perpendicular magnetic driving field stronger than 200mT. Interestingly, the dynamic behavior of the moving magnetic domain wall driven by perpendicular magnetic field pulses is explained by charging- and discharging-like behaviors of an electrical RC-circuit model, where the charging and the discharging of magnetic charges on the nanowire planes are considered. The concept of the RC-model-like dynamic characteristic of the magnetic domain wall might be promising for the applications in spintronic functional devices based on the magnetic domain wall motion.
文摘BACKGROUND Ureteropelvic junction obstruction(UPJO)is a common congenital urinary tract disorder in children.It can be diagnosed as early as in utero due to the presence of hydronephrosis or later in life due to symptomatic occurrence.AIM To evaluate the discrepancy between dynamic contrast-enhanced magnetic resonance urography(dMRU)and scintigraphy 99m-technetium mercaptoacetyltriglycine(MAG-3)for the functional evaluation of UPJO.METHODS Between 2016 and 2020,126 patients with UPJO underwent surgery at Robert DebréHospital.Of these,83 received a prenatal diagnosis,and 43 were diagnosed during childhood.Four of the 126 patients underwent surgery based on the clinical situation and postnatal ultrasound findings without undergoing functional imaging evaluation.Split renal function was evaluated preoperatively using scintigraphy MAG-3(n=28),dMRU(n=53),or both(n=40).In this study,we included patients who underwent surgery for UPJO and scintigraphy MAG-3+dMRU but excluded those who underwent only scintigraphy MAG-3 or dMRU.The patients were divided into groups A(<10%discrepancy)and B(>10%discrepancy).We examined the discrepancy in split renal function between the two modalities and investigated the possible risk factors.RESULTS The split renal function between the two kidneys was compared in 40 patients(28 boys and 12 girls)using scintigraphy MAG-3 and dMRU.Differential renal function,as determined using both modalities,showed a difference of<10%in 31 children and>10%in 9 children.Calculation of the relative renal function using dMRU revealed an excellent correlation coefficient with renal scintigraphy MAG-3 for both kidneys.CONCLUSION Our findings demonstrated that dMRU is equivalent to scintigraphy MAG-3 for evaluating split renal function in patients with UPJO.
